Effect of pretreatment with 5,7-DHT on MKC-242-induced increase in extracellular dopamine levels in the prefrontal cortex. MKC-242 at 1.0 mg kg−1 was injected s.c. 14 days after rats were injected i.c.v. with saline and 5,7-DHT at 150 μg. Points are means±s.e.mean of 4–8 rats. aP<0.05, bP<0.01, cP<0.001, compared with 5,7-DHT/CMC (two-way ANOVA followed by Tukey's test).